How to setup the correct IP addresses?

I have one static external IP address. And I have one local Server computer with IP: The IIS and Mail server is running on computer with IP:

Now I setup my DNS configuration as seen in my screenshot. Server configuration sample

But Registrar provider tells me, that I made fault on NS and A records. I could not imagine where. How to correct setup a DNS server?

PS: For public, I changed the domain name. I found some tutorials but most with fake values. My question is using reasonable values.

1 Answer 1


To make things easier I'll presume your setup is very simple...
The DNS server in the screenshot will be your internal DNS - this is different to your external and external clients won't resolve because that is designated a private subnet - not routable over the public internet.

You will need to configure your external DNS servers to point to instead of and
Then on your firewall port forward all the services you want to provice to the public e.g.

25 for MAIL
80 for HTTP
443 for HTTPS

This will get you your desired result.


ok so to start at the beginning you have a domain ... mydomain.com

You need to make sure it resolves correctly on both the public internet and your network. In your scenario the easiest thing to do is running a public and private DNS for your setup.
I.e. on your public DNS provider e.g. godaddy/123-reg/uk2 (or whatever it is), point the host A record and the wild card subdomain to this will make sure everything resolves to that IP.

This will make sure every external client knows who mydomain.com is. Then just open the ports on the firewall and forward them to the right server.

I presume you want to be able to access the sites internally too - Configure your local / private DNS server with a new forward lookup zone with mydomain.com and configure it with and .101

This will make sure internal clients can resolve the correct internal address otherwise it will only resolve the public IP and your internal clients won't know where to send the traffic. (unless of course you NAT them on the router although I'm guessing that's out of yours skillset for the time being).

  • Thanks a lot for your comment. I am sorry but I need to rephrase for my understanding. All of the listed entries should be ? or just some rows?
    – Nasenbaer
    Sep 29, 2014 at 22:29
  • No .. what you have in that DNS server in screenshot is ok. What you need to change is external DNS e.g. godaddy, 123-reg, zoneedit whatever DNS provider you use for your external domain.
    – Rhys Evans
    Sep 29, 2014 at 22:37
  • Internal DNS should not be a publicly accessible domain name but should be a subdomain blog.varonis.com/active-directory-domain-naming-best-practices
    – Rhys Evans
    Sep 29, 2014 at 22:44
  • CNAME can be the IP of local computer or is it not possible? Is www > allowed to forward to me IIS service computer or what to write there?
    – Nasenbaer
    Sep 29, 2014 at 22:52
  • No - for publicly accessible services it needs to be done through your external DNS provider - if you are trying to host your internal and external DNS on one server a Windows box won't work - you'll have to use BIND with views
    – Rhys Evans
    Sep 29, 2014 at 22:59

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